The invention disclosed herein is related to shaped charge perforators for use in oil wells, and is more particularly related to attachment means for attaching charges to the wires of a bi-wire type body for oil well perforators.
In the perforation of an oil well, it is desirable to assemble perforating units into guns having a plurality of units in a desired spacing and orientation. These perforating guns are assembled at one central point and taken to the site of an oil well in a standard configuration having a set orientation and density of charges per unit length. Many times after arriving at the site of an oil well, it is necessary to strip off some of the perforating units to change the density or orientation as may be dictated by the needs of the particular well or the preference of the owner or operator of the well.
In the prior art perforating guns are assembled with the unit strung together by sliding the perforating units onto either wires or strips with spacers between the units to achieve the desired spacing. Various means have been used to attach the perforating units to either strips or wires of the perforating gun. In this type design, if it is desirable to remove perforating units or change the density of the perforating units per unit length, it is necessary to strip off the charges and intermediate spacers one at a time and rethread the units and spacers in the desired configuration or density. In the hostile environment many times present at an oil well site, this is very difficult and time consuming.
Also known in the prior art, are perforating guns having bent wires for accepting perforating units at periodic bends in the wires. The bends are usually dimensioned such that they bend around the body of the perforating unit and are held in place by various attachment means. In such an assembly the charges may only be inserted where a bend is present in the wires and thus changing the density of the perforating units can only be accomplished by either placing or removing perforating units from the bent sections of the wire.
In the present invention a simple method and apparatus is disclosed for quickly attaching perforating units to a bi-wire carrier wherein each of the wires of the carrier is placed in ear shaped extensions of the perforating units, and a screw is tightened from another extension for trapping the wire in the ear shaped extension between an appropriate cavity in the case and the screw. This apparatus thus results in perforating units which may be quickly attached or removed from between two wires by simply loosening or tightening screws to engage the perforating units at the desired location on the wire carrier. To increase the density of the perforating units it is only necessary to loosen the screws and move the perforating units to a closer spacing and insert any additional perforating units which may be desired.
To remove units from a perforating carrier and decrease their density it is only necessary to remove the undesired units and loosen the screws of the other units and move the units to the desired spacing. The perforating units are then reattached at the desired location by simply tightening the screws.